Navigating between Cupertino routes not working - flutter

Question

I have a simple app that uses the Cupertino App. I have four tabs at the bottom that allows me to navigate between pages. on the last tab AddCashPage I've added on button on the page that will allow me to navigate to the second page CalendarPage
The app is only one page so I'll post the entire thing
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
// import 'styles.dart';
import 'pages/summary_page.dart';
import 'pages/calendar_page.dart';
import 'pages/remove_cash_page.dart';
final scakey = new GlobalKey<_BottomState>();
class CashOnHandApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Cash on Hand',
home: HomePage(),
);
}
}
class HomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: CupertinoPageScaffold(
navigationBar: CupertinoNavigationBar(
middle: const Text('Cash on Hand'),
),
child: Bottom(key: scakey),
),
);
}
}
class Bottom extends StatefulWidget {
Bottom({Key key}) : super(key: key);
#override
_BottomState createState() => _BottomState();
}
class _BottomState extends State<Bottom> {
final myKey = new GlobalKey<_BottomState>();
int _selectedIndex = 0;
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
print(_selectedIndex);
});
}
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
return CupertinoTabScaffold(
key: myKey,
tabBar: CupertinoTabBar(
onTap: _onItemTapped,
items: const <BottomNavigationBarItem>[
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.home),
title: Text('Summary Page'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.clock_solid),
title: Text('Calendar'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.minus_circled),
title: Text('Remove Cash'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.plus_circled),
title: Text('Add Cash'),
),
],
),
tabBuilder: (context, index) {
switch (index) {
case 0:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: SummaryPage(),
);
});
case 1:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: CalendarPage(),
);
});
case 2:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: RemoveCashPage(),
);
});
case 3:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: AddCashPage(),
);
});
}
},
);
}
}
class AddCashPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
CupertinoButton(
onPressed: () {
scakey.currentState._onItemTapped(1);
},
child: Text('data'),
),
],
),
);
}
}
I was able to use scakey.currentState._onItemTapped(1); on material app before so I thought it would work the same on a Cupertino App

Answer 1

According to official document https://api.flutter.dev/flutter/cupertino/CupertinoTabScaffold/tabBar.html
providing a different CupertinoTabBar.currentIndex does not affect the scaffold or the tab bar's active tab index. To programmatically change the active tab index, use a CupertinoTabController.
You need to use tab controller
code snippet
final CupertinoTabController _controller = CupertinoTabController();
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
_controller.index = index;
print(_selectedIndex);
});
}
working demo
full code
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: HomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
#override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
final scakey = new GlobalKey<_BottomState>();
class CashOnHandApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Cash on Hand',
home: HomePage(),
);
}
}
class HomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: CupertinoPageScaffold(
navigationBar: CupertinoNavigationBar(
middle: const Text('Cash on Hand'),
),
child: Bottom(key: scakey),
),
);
}
}
class Bottom extends StatefulWidget {
Bottom({Key key}) : super(key: key);
#override
_BottomState createState() => _BottomState();
}
class _BottomState extends State<Bottom> {
final myKey = new GlobalKey<_BottomState>();
int _selectedIndex = 0;
final CupertinoTabController _controller = CupertinoTabController();
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
_controller.index = index;
print(_selectedIndex);
});
}
#override
void initState() {
super.initState();
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return CupertinoTabScaffold(
controller: _controller,
key: myKey,
tabBar: CupertinoTabBar(
onTap: _onItemTapped,
items: const <BottomNavigationBarItem>[
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.home),
title: Text('Summary Page'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.clock_solid),
title: Text('Calendar'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.minus_circled),
title: Text('Remove Cash'),
),
BottomNavigationBarItem(
icon: Icon(CupertinoIcons.plus_circled),
title: Text('Add Cash'),
),
],
),
tabBuilder: (context, index) {
switch (index) {
case 0:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: SummaryPage(),
);
});
case 1:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: CalendarPage(),
);
});
case 2:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: RemoveCashPage(),
);
});
case 3:
return CupertinoTabView(builder: (context) {
return CupertinoPageScaffold(
child: AddCashPage(),
);
});
}
},
);
}
}
class AddCashPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
CupertinoButton(
onPressed: () {
scakey.currentState._onItemTapped(1);
},
child: Text('data'),
),
],
),
);
}
}
class SummaryPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("Summary");
}
}
class CalendarPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("Calendar");
}
}
class RemoveCashPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("RemoveCash");
}
}